bcachefs: fsck: Work around transaction restarts

In check_extents() and check_dirents(), we're working towards only
handling transaction restarts in one place, at the top level - but we're
not there yet. check_i_sectors() and check_subdir_count() handle
transaction restarts locally, which means the iterator for the
dirent/extent is left unlocked (should_be_locked == 0), leading to
asserts popping when we go to do updates.

This patch hacks around this for now, until we can delete the offending
code.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/fsck.c

@@ -1146,7 +1146,7 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
 	struct inode_walker_entry *i;
 	struct printbuf buf = PRINTBUF;
 	int ret = 0;
-
+peek:
 	k = bch2_btree_iter_peek(iter);
 	if (!k.k)
 		goto out;
@@ -1173,6 +1173,15 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
 		if (ret)
 			goto err;
 	}
+
+	if (!iter->path->should_be_locked) {
+		/*
+		 * hack: check_i_sectors may have handled a transaction restart,
+		 * it shouldn't be but we need to fix the new i_sectors check
+		 * code and delete the old bch2_count_inode_sectors() first
+		 */
+		goto peek;
+	}
 #if 0
 	if (bkey_cmp(prev.k->k.p, bkey_start_pos(k.k)) > 0) {
 		char buf1[200];
@@ -1464,7 +1473,7 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 	struct inode_walker_entry *i;
 	struct printbuf buf = PRINTBUF;
 	int ret = 0;
-
+peek:
 	k = bch2_btree_iter_peek(iter);
 	if (!k.k)
 		goto out;
@@ -1492,6 +1501,11 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 			goto err;
 	}
 
+	if (!iter->path->should_be_locked) {
+		/* hack: see check_extent() */
+		goto peek;
+	}
+
 	ret = __walk_inode(trans, dir, k.k->p);
 	if (ret < 0)
 		goto err;